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<h1 class="title">plugin.cpp 示例文件</h1>
<span class="subtitle">qmlextensionplugins/plugin.cpp</span>
<!-- $$$qmlextensionplugins/plugin.cpp-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp">

  <span class="comment">/****************************************************************************
  **
  ** Copyright (C) 2017 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, you may use this file under the terms of the BSD license
  ** as follows:
  **
  ** &quot;Redistribution and use in source and binary forms, with or without
  ** modification, are permitted provided that the following conditions are
  ** met:
  **   * Redistributions of source code must retain the above copyright
  **     notice, this list of conditions and the following disclaimer.
  **   * Redistributions in binary form must reproduce the above copyright
  **     notice, this list of conditions and the following disclaimer in
  **     the documentation and/or other materials provided with the
  **     distribution.
  **   * Neither the name of The Qt Company Ltd nor the names of its
  **     contributors may be used to endorse or promote products derived
  **     from this software without specific prior written permission.
  **
  **
  ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  ** &quot;AS IS&quot; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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  ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.&quot;
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/</span>

  <span class="preprocessor">#include &lt;QtQml/QQmlExtensionPlugin&gt;</span>
  <span class="preprocessor">#include &lt;QtQml/qqml.h&gt;</span>
  <span class="preprocessor">#include &lt;qdebug.h&gt;</span>
  <span class="preprocessor">#include &lt;qdatetime.h&gt;</span>
  <span class="preprocessor">#include &lt;qbasictimer.h&gt;</span>
  <span class="preprocessor">#include &lt;qcoreapplication.h&gt;</span>

  <span class="comment">// Implements a &quot;TimeModel&quot; class with hour and minute properties</span>
  <span class="comment">// that change on-the-minute yet efficiently sleep the rest</span>
  <span class="comment">// of the time.</span>

  <span class="keyword">class</span> MinuteTimer : <span class="keyword">public</span> <span class="type"><a href="../qtcore/qobject.html">QObject</a></span>
  {
      Q_OBJECT
  <span class="keyword">public</span>:
      MinuteTimer(<span class="type"><a href="../qtcore/qobject.html">QObject</a></span> <span class="operator">*</span>parent) : <span class="type"><a href="../qtcore/qobject.html">QObject</a></span>(parent)
      {
      }

      <span class="type">void</span> start()
      {
          <span class="keyword">if</span> (<span class="operator">!</span>timer<span class="operator">.</span>isActive()) {
              time <span class="operator">=</span> <span class="type"><a href="../qtcore/qtime.html">QTime</a></span><span class="operator">::</span>currentTime();
              timer<span class="operator">.</span>start(<span class="number">60000</span><span class="operator">-</span>time<span class="operator">.</span>second()<span class="operator">*</span><span class="number">1000</span><span class="operator">,</span> <span class="keyword">this</span>);
          }
      }

      <span class="type">void</span> stop()
      {
          timer<span class="operator">.</span>stop();
      }

      <span class="type">int</span> hour() <span class="keyword">const</span> { <span class="keyword">return</span> time<span class="operator">.</span>hour(); }
      <span class="type">int</span> minute() <span class="keyword">const</span> { <span class="keyword">return</span> time<span class="operator">.</span>minute(); }

  <span class="keyword">signals</span>:
      <span class="type">void</span> timeChanged();

  <span class="keyword">protected</span>:
      <span class="type">void</span> timerEvent(<span class="type"><a href="../qtcore/qtimerevent.html">QTimerEvent</a></span> <span class="operator">*</span>) override
      {
          <span class="type"><a href="../qtcore/qtime.html">QTime</a></span> now <span class="operator">=</span> <span class="type"><a href="../qtcore/qtime.html">QTime</a></span><span class="operator">::</span>currentTime();
          <span class="keyword">if</span> (now<span class="operator">.</span>second() <span class="operator">=</span><span class="operator">=</span> <span class="number">59</span> <span class="operator">&amp;</span><span class="operator">&amp;</span> now<span class="operator">.</span>minute() <span class="operator">=</span><span class="operator">=</span> time<span class="operator">.</span>minute() <span class="operator">&amp;</span><span class="operator">&amp;</span> now<span class="operator">.</span>hour() <span class="operator">=</span><span class="operator">=</span> time<span class="operator">.</span>hour()) {
              <span class="comment">// just missed time tick over, force it, wait extra 0.5 seconds</span>
              time <span class="operator">=</span> time<span class="operator">.</span>addSecs(<span class="number">60</span>);
              timer<span class="operator">.</span>start(<span class="number">60500</span><span class="operator">,</span> <span class="keyword">this</span>);
          } <span class="keyword">else</span> {
              time <span class="operator">=</span> now;
              timer<span class="operator">.</span>start(<span class="number">60000</span><span class="operator">-</span>time<span class="operator">.</span>second()<span class="operator">*</span><span class="number">1000</span><span class="operator">,</span> <span class="keyword">this</span>);
          }
          <span class="keyword">emit</span> timeChanged();
      }

  <span class="keyword">private</span>:
      <span class="type"><a href="../qtcore/qtime.html">QTime</a></span> time;
      <span class="type"><a href="../qtcore/qbasictimer.html">QBasicTimer</a></span> timer;
  };

  <span class="keyword">class</span> TimeModel : <span class="keyword">public</span> <span class="type"><a href="../qtcore/qobject.html">QObject</a></span>
  {
      Q_OBJECT
      Q_PROPERTY(<span class="type">int</span> hour READ hour NOTIFY timeChanged)
      Q_PROPERTY(<span class="type">int</span> minute READ minute NOTIFY timeChanged)

  <span class="keyword">public</span>:
      TimeModel(<span class="type"><a href="../qtcore/qobject.html">QObject</a></span> <span class="operator">*</span>parent<span class="operator">=</span>nullptr) : <span class="type"><a href="../qtcore/qobject.html">QObject</a></span>(parent)
      {
          <span class="keyword">if</span> (<span class="operator">+</span><span class="operator">+</span>instances <span class="operator">=</span><span class="operator">=</span> <span class="number">1</span>) {
              <span class="keyword">if</span> (<span class="operator">!</span>timer)
                  timer <span class="operator">=</span> <span class="keyword">new</span> MinuteTimer(<span class="type"><a href="../qtcore/qcoreapplication.html">QCoreApplication</a></span><span class="operator">::</span>instance());
              connect(timer<span class="operator">,</span> <span class="operator">&amp;</span>MinuteTimer<span class="operator">::</span>timeChanged<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&amp;</span>TimeModel<span class="operator">::</span>timeChanged);
              timer<span class="operator">-</span><span class="operator">&gt;</span>start();
          }
      }

      <span class="operator">~</span>TimeModel() override
      {
          <span class="keyword">if</span> (<span class="operator">-</span><span class="operator">-</span>instances <span class="operator">=</span><span class="operator">=</span> <span class="number">0</span>) {
              timer<span class="operator">-</span><span class="operator">&gt;</span>stop();
          }
      }

      <span class="type">int</span> minute() <span class="keyword">const</span> { <span class="keyword">return</span> timer<span class="operator">-</span><span class="operator">&gt;</span>minute(); }
      <span class="type">int</span> hour() <span class="keyword">const</span> { <span class="keyword">return</span> timer<span class="operator">-</span><span class="operator">&gt;</span>hour(); }

  <span class="keyword">signals</span>:
      <span class="type">void</span> timeChanged();

  <span class="keyword">private</span>:
      <span class="type"><a href="../qtcore/qtime.html">QTime</a></span> t;
      <span class="keyword">static</span> MinuteTimer <span class="operator">*</span>timer;
      <span class="keyword">static</span> <span class="type">int</span> instances;
  };

  <span class="type">int</span> TimeModel<span class="operator">::</span>instances<span class="operator">=</span><span class="number">0</span>;
  MinuteTimer <span class="operator">*</span>TimeModel<span class="operator">::</span>timer<span class="operator">=</span>nullptr;

  <span class="keyword">class</span> <span class="type">QExampleQmlPlugin</span> : <span class="keyword">public</span> <span class="type"><a href="qqmlextensionplugin.html">QQmlExtensionPlugin</a></span>
  {
      Q_OBJECT
      Q_PLUGIN_METADATA(IID QQmlExtensionInterface_iid)

  <span class="keyword">public</span>:
      <span class="type">void</span> registerTypes(<span class="keyword">const</span> <span class="type">char</span> <span class="operator">*</span>uri) override
      {
          Q_ASSERT(uri <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">&quot;TimeExample&quot;</span>));
          qmlRegisterType<span class="operator">&lt;</span>TimeModel<span class="operator">&gt;</span>(uri<span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="string">&quot;Time&quot;</span>);
      }
  };

  <span class="preprocessor">#include &quot;plugin.moc&quot;</span>

</pre>
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<!-- @@@qmlextensionplugins/plugin.cpp -->
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